The use of predatory insects, including coccinellids and chrysopids, as biological control agents to suppress pest populations on either economically important crops or in home gardens, is widely accepted and recognized by the general public and biological control practitioners (see references in, Obrycki, J. J. and Kring, T. J., 1998, Annu. Rev. Entomol. 43:295-321; and Canard, M., et al., 1984. Biology of Chrysopidae, pp. 294, DR W. JUNK Publishers, The Hague/Boston/Lancaster).
There have been significant successes in using coccinellids and chrysopids to suppress whitefly, aphid, mealybug, scale and mite populations (Gerling, D. 1990). Natural enemies of white flies: predators and parasitoids. In Whiteflies: Their Bionomics, Pest Status and Management. (D. Gerling, ed.), pp. 147-185. Andover: Intercept Ltd.; and in Frazier, B. D. 1988, Coccinellidae. in Aphids-Their Biology, Natural Enemies and Control. (A. K. Minks, P. Harrewijn, eds.), Vol. B, pp. 231-247. New York, Amsterdam: Elsevier; New, 1975).
Despite the significant use of these two groups of predatory insects for biological control, very little is known about the mechanisms involved in prey location (e.g. van Emden, H. F., and Hagen, K. S., 1976, Environ. Entomol. 5:469473; and HAGEN, K. S. 1987. Nutritional ecology of terrestrial insect predators. In Nutritional Ecology of Insects, Mites, Spiders, and Related Invertebrates, (Slansky and Rodriguez, eds.), pp. 533-577. New York: Wiley and Sons.). In particular, it is not known whether the predators are able to use odors directly from their prey or their host plant to eventually locate their prey. Because of the dispersal behavior of many aphidophagous species and their polyphagous nature (Frazier, 1988), attractive compounds could be useful in retaining predaceous insects in fields where they were released.
The twelve spotted lady beetle, Coleomegilla maculata (Degeer) and the golden eyed green lacewing, Chrysoperla carnea (Stephens) are two of the most common aphid predators found in field crops in the eastern United States. They are especially abundant in crops such as cotton, corn and alfalfa. In corn these two predatory species feed on aphids and European corn borers (Obrycki and Kring, 1998; Phoofolo, M. W, 1997, pp. 172, Ph.D. thesis, Iowa State University; Sparks, A. N., et al., 1966, J. Econ. Entomol. 59:104-107; and Udayagiri, S., 1996, Agric. Zool. Rev. 7:181-216), and in alfalfa they feed on aphids and alfalfa weevil larvae (Giles, K. L., et al., 1994, Biol. Cont. 4:170-177).
In spite of the successes that have been reported using predatory insects to control pests, there is currently a need for methods to attract predatory insects to target areas. There is also a continuing need for additional forms of pest control that do not require the use of hazardous or toxic chemicals.
Applicant has discovered that certain plant volatiles emitted for instance from corn, alfalfa, and from plant parts such as flowers and fruits of various species are useful for attracting predatory insects. Accordingly, the invention provides a method for attracting a predatory insect to a target area comprising applying an effective amount of a plant volatile in or near the area. Preferably, the plant volatile is not xcex2-caryophyllene or (E)-xcex2-Farnesene.
The invention also provides a composition comprising an effective insect attracting amount of a plant volatile, and a suitable carrier.